Variable-load air-spring.



R. LIEBAUr VARIABLE LOAD Am SPRING.

APPLICATION FILEDl MAY I3, 1913- R. LIEBAUt VARIABLE LOAD AIR SPRINGI- APPLICATION FILED MAY 1s, 1913.

R. LIEBAU. VARIABLE LOAD AIR SPRING. APPLICATION FILED MA'Y 13 1913- ILM mm HIS A TORNEY IN FACT relation where two bodies lare so associated that resilient movement. tliei'ehetiveen is de- STATE BEST AvAiLAsLE coe PATENT OFFLCE .RICHARD LEBAU, OFSWISSVALE, PENNSYLVANIA, ASSIGNOR IO THE WESTINGIA-IOUSE AIR SPRING QOMPANY, A CORPORATION OF'PENNSYLVANIA.

VARIABLE-LOAD AIR-SPRIN G.

Specification of Letters Patent.

To all whom t may concern.'

lie it known that I, -Rieiiiiiin LIEBAU, a citizen of the United States, and a resident ot' Hivissvale, in the county of Allegheny and State of Pennsvlvauia,- have made a new vaud uset'ul Invention in Vaiialile-Load Airb'pi'ings, otivhieli the following is a specifi* cation.

'lhis invention relates to an elastic tluid cushion device.

ri the present/case,-tlie invention is embodied in a Huid cushion device adaptedior use asa spring which may lie used in any siiable, `and the general object inview has been to euil'iody the principles ot resilient support by an elastic fluid, such as air or any othei gas, in a eon'iinercially practical, self# contained, fluid-tight cushion device adapted to serve all 'the purposes and functions ot a spriiio'.

In my present inveiition'a fluid tight joint is providedbetween sliding suri'aees. This is attained by means of a cylindricalv or cupleather packingl tightly clamped in.one of the sliding nienihei's and having its jfree edge presentedin the direction of the high' pressure and yieldingly forced into engagement with the outer wall of the sliding jointby means ot' a rigid cone spring pressed in af' direction parallel with the axis ,ot the device. It also ini'olves the use of a collecting space for the oil or other sealing tuid which finds its ii'arv past the leather packing, and oi a pump within the device for pumping the escaped oil back to the interior oi' comv ll'essioii chamber oi: 'the device.

ln motor vehicles, vsuch as trucks and delivery wagons, when utilizing steel springs,

it is necessary to inake the springs stiff l enough to carry the full load to which the trucks or wagons may be subjected, and

when this is done. ot course, the springs are pi acticedlyineffective unless the load'is carried. ./niobjeet oi' this invention to provide an elastic lHuid cushion device. which' will not only he effective when' lthe vehicle 'to which it is attached is loaded, but when the same is without load, and for that purpi'ise l provide a cushion device having tivov effective diaii'ieters'fwne to serve an effective cushion when the vehicle is Without load Appliction filed May 13, 15.313. Serial No. 767,312.

Patented Mar.' 13', 1917.

i *or when lightly loaded7 andthe other to serve when the vehicle is fully loaded or loaded beyond a determined point. tion, A I form a. closed chamber by means of three, telescopiiailly arranged n'ieiiiheis,--an 'inner member having a closed outer end, an outer nieiiibei" having a closed' outeii'eni'l, and an intermediate member bridging the space between the other two and telescopic-ally arranged outsideo't the inner member and in side oi the outer member, whereby a ciisliion chamber of two effective diameters is formed having two sliding joints, ,the smallerdiaineter serving as the cushionfor the light loads, and the larger serving as the cushion for the heavy loads. I

The three members are so arranged that the intermediate member floats between the two and automatically assumes theposition in accordance with the load conditions.

Iii the presentcase, while there are two sliding joints to the closed chamber but one oil collecting space is employed and hutfone pump for returning the oil from the collecting s-pac't'o the interior ol the chamber.

Without any'idea oi" limiting this invention, but for the sake of clearness, the deyvice will hereinafter be referred to as an air spring.

In the drawings i I I. Figure i is a! longitudinal sectional view of an airspring constructed in accordance with this invention i Fig. 2 is a View of the spring shown in Fig` l ivith'the intermediate member re-Y merals of. reference:

The device consists of an inner member Iiithe present eiiibi dIneIit-'"Of the invenhavinga cylindrical portion 4t vand a head prov ided with a vfilling opening' adapted to be' closed by means of a screw threaded plug providedfiwith lan airwvalve such as those' commonly -used torlpneinnatic tires. The lower end of cylindrical member 4 is iiiteinally threaded at 7 and is faced to receive arcup-leather packing 8 the enter or free edge 9 ot' which extends parallel to, the axis ot cylindrical portion 4. The cup-e .leather packing is secured in place by means `of a washer l0 and a nut 1l threaded into i 18, and this is placed in the cylindrical member at 7. The nut 11 has an enlarged portion 12 provided with a groove for receiving a leather packing 13; a cone-shaped expander ring 1l bears against the enter or free edge S) of the eupleather packing and by means of the spring 15 which is located between expander ring 14 and the enlarged portion l2 ot nut 11l yieldingly forces Said outer or free edge 9 o1 the cup-leather packing into engagement with the inner wall of intermediate member 16 hereinafter referred to. Nut 11 is provided with an upwardly extending lip 17 which with cylindrical portion 4 of the inner member forms an oil retainingr chamber connectionV with the space around the cup-leather packing by means ot duets 19 drilled through the nut. The leather packing 13 bearing.,r against the inner surface of intermediate member 16 forms a closed-iii space for oil and retains the oil coming from the reservoir 18 in connection with the outer or free edge 9 of the cup-leather packing. intermediate member 1G throughout the major portion of its length is cylindrically formed and above an inwardly extending flange 20 (which is inter- A nally screwthreaded) is machined so as to present 'a smooth surface to cup-leather packing S. The lower end ot' intermediate member 1G is provided with an outwardly extending llange 21 the under side ot which is faced to receive a cup-leather packing 2'2 which has its free edgD extending parallel to the axis of the device and which bears against .the inner machined surface of an outer cylinder member 21. i

The lower end ot' intermediate member 16 is externally threaded at to receive a nut 2G which carries a leather packing Q7 for closing in an oil retaining space around or in connection with the outer or Jfree edge of cup-leather ,packing 22. The outer or free edge 23 of cup-leather S22 is yieldinglv forced into engagement with the inner surtace of outer member 2l by means of a. cone expander ring 2S which is yieldingly )ressed' against the inner edge of the. cup-lent er by means of a spring 29 confined in place by the nut 2G.

Intermediate member 16 is provided with an inwardly extending wall 30 which forms an oil reservior 31 for feeding through ducts 3Q the space closed in by leather packing 27. A. boss 33 extending inwardly from intermediate member lG carries the pump for returning the oil or other sealing fluid which I leaks past cup-leather packings S and 22 to the interior or cushion chamber of the 33 1s bored out at 34 to plunger 35 and a check spring. rl`he boss receive a pump valve housing 36.

The check valve housing 36 is preferably sweated into its bore in boss 33 and is pro vided with a valve chamber 37 within which in the bottom of the plunger.

Yas to form a normally restricted a ball valve 38 is located. The ball is retained in an operative position by means of a retaining screw 59. The valve housing 3G is provided with an inlet passage l0 which communicates with a passage 11 cored in boss 33 and which leads from space 42 above flange 21 to passage -LO in the valve housing. An outlet 43 connects valve chamber 3T above the ball valve to the pump chamber 31. Pump plunger 35 is formed hollow from top to bottom and a ball cheek valve 14 is seated A stop plug 45 is screwed into the bottom of bore and forms a stop for the. downward motion of the pump plunger, and it will be seen that the pump plunger moves down far enough to seal the inlet passage 43 to the pump.

At 1li intermediate member 1li is provided with an inwardly extending llange and loosely mounted on pump plunger 35 is a disk 47 which cooperates with said flange to form a motor for operating the pump.` The disk 117 lies between two collars 4S and L1t); 18 is preferably formed integrally with the. pump plunger, and 49 is threaded on to the upper end of the plunger. The disk 47 is supported out of contact with collar 48 by means of a coil spring 50. This'spring will keep the disk from adhering to collar 48 on account of the viscosity of the oil or other sealing lluid, and also will maint-ain the disk 4T in such position passage heedge of the disk and inwardly extending liange 46. A coil spring 51 confined between collar 49 and a spring retainer 52 threaded into flange Q0 tends to yieldingly hold the pump plunger toward the limit of its downward n'iovement. Spring retainer is connected from its inner portion 53 te its outer portion 5t by means of webs and between these webs the` liquid in the interior of` the device is free to pass. The bottom 6() of outer mem'- ber 211 is provided with an eye G1 adapted to be attached through suitable shackles or links and levers to the vehicle running lgear or more paltcularly to the steel springs forming a part thereof. Bottom 4is provided with a drain plug (32 in order that it it is necessary liquid may be drained from the interior of the spring. Screwed on to the upper `end of member 24 is a retaininw ring 63 provided with an inwardly exten( ing liange 64 adapted on the extreme outer movements of the air spring to contact with a leather butter ring 65 which rests upon the serrated outer edge ol a flange 6G formed on intermediate member 1G. The serrations in this liange permit the oil to pass therebetween into collecting space 42. that is, the oil which leaks past upper cup-leather packtween the outer ings. A

hreaded on to thel upper cuter edge ol intermediate member 1G is a flange retainer laill'er ring 68 which serres as 3i ybuffer hetween said llange andban inwardly7 eXtend-'- ing wall 69 which ]oins head`5 to cylindrical portion 4.

An outer. guard or cylinder 70 threaded on to a dependinglange 71 of' the head 5 is :wlaptedl to be. rigidly attached to the \'e hiele Chassis upon which the spring .is to he nsedfand a pad is furnished for that purpose. 'l`he ont-er guard or cylinder 70 is provided with' an inspection plate 7? which gives access to aportion of the interior of' the device.

Between shoulder M and the lower edge 75 ot' depending liange, 71 a retainer in ernloer .76 is clamped. rlhis retainer vmember is provided with an inwardly extendino'la-nge 77 which adapted to eontact'with an ontirardly extending flange 78 on retainer ring 6T when the intermediate member 16 reaches the dow wardliniit of its travel'during as- ;enrhling;` lt, however/idees not so aet dur` ng the ,operation ofwtlie deviee because `the lower eilge S2 of retainerring 63,*conta`ets 4with a 'leather hnfter ringfS-ythe' distance Setweenll and `the briller' ring; S3" being-v less han the.' distance between the flange 7' and he llange of' the retainingringi'.'

An ontwardl'y extending 'liange 8O` forme-d n retainer member 7 6 holds aleather. buffer ing-Elin place so thatv it willgeontactwith ie opper face of retaining ring '63 when le enter cylinderv 24 reaches theinnerlimit 'itstravet` Under normi l operating-i conditions the teriorof the. spring is ehargednvith a flermined, quantity of sealing liquid for the 4oir-ings, sneh for-example as nih-and itis` sofeharged with ,compressed air, which. moving lite `ls to extend the springby ier element 4 and its outer' elenientA 'ay from each other, and forms the suprting medium for the chassis or holly of s vehicle.v l Ulu-ing light loads von the eliassis the inmediate sleeve 16 is moved upwardly hy son of the unbalanced internal pressure ing; on its lower edge and on the-lower face the unt Q6 so that the butler 6C andthe hion 65 carried by it are moved against inwardly' vextending llange'fll: of the .ar member 24; it being understood that pressure inthe `annular ssage 42, and exterior passa eonnnunieating there` l, is approximately atmospherie pressure4 materially less than the pressure Within interior chambers vofthe spring. Under conditions, the. sleeve 16 is in effect ed to the outer member .24 and the inil pressure exertedon its lower eel-ge ou the lower annular face of the nut 26 lo supporting-effect whatever lint merely rts a strain to the cylindrical wall `oli nner member 2 4 andoperatesA to lock of the-'sleeve to niore down ell'eetire areafof the spring is ABES'TAVILABLE this member and the sleeve together. The eripansion and contraction ot the spring' in response to variations .in the relative posi tions ot the running gear and the ehassisg the vehicle. rause relative. motion between the inner meunier #i and *he sleeve 16 and the unbalanced interior pressure acting on the member-fl is the only pressure' operative insupporting the load. An exaxniinxtion` of thejdrawings will showthat this load'supporting torce is equal to the internal pres- V-eure multiplied by the area of a circle har?. in aF a diameter equal to the internaldiameter ofthe sleeve 16. l

During; hea\ T l 'loy oads the weighttransmitted' hy the Chassis to the niemher 4, (le-presses; this inen'iher tosueh an extent that its. out- "wardly extending; wall 69 engages the huller ring 68 ,ou `the flange retainer ringr'- which is mounted onthefsltere 16. 'A further de' .pression ol" the ineinher #l will therefore more the hul'er ring 65, ot the sleeve. out ,of engagement with the flange 64, of the .outer nieinher "2%, and "-'ause the eup parkingy wardly along theiinneriaee ofthe 'member 24. As soon as the' lorliing engagement 'hetweenthe sleeve* 16 andthe xnenxher 2J; is lorolren.v the nnhal-j anced pressure oceasionedV hy' the iuternai Y pressure operating onfthe l o\ ver faee` of 'the nut 26 amlrtherlower edge' ot' the sleere. 16 Y' transrnits an npwardjthrust: through the buffer. 68 tojthe inner'or chassis supporting' inieniher 4;.- It is'theret'ore apparent that Vthe' increased h vvthe area of the lmverfaee of the annular nut plus the area 'of the. lower edge' of the sleeve; Y v. in other words the eli'eetive supporting torce of the spring. under heavy loads, is equal to tl'ie'internal pressure times the area of a` circle having' a diameter equal .to the inten. nal chamber of the'sleeve24. f During the expansionsand contractions of the spring, the. oil contained. in "it will surge-first in one direetii'in. and then in the othervand will operate the pump plunger 35 through the agenry ol the disk gli', and the*y sealing liquid leaking past both'the packing 8 and the packing 22 will hereturned to the interior of the spring from the Charnber 12.

In accordance with the previsions of the patent statutes' I'hare described the prineipleof operation of my invention together withthe device which lnow'consider t0 rep. resent the best embodiment thereof, bntj I .desire to have' it understood that: the deviee shonuris only-illustrative and vthat the ini rention can he' carried out in other Ways.

Having thus described my .invention what 4 claim is: i, i. 1, A cushioning device comprising, telef; scopically arrangedvmembers having a sliding joint therebetween and lormingnninclosed eliarnloer of variable volume-trie caeach olf the 'olumetric capacity, a floating member telescopically arranged with both of said members and adapted to move under conditions of light load with one and under heavy. load conditions with the other of said first mentioned members, a separate packing between 'said floating member and each of said ir'st `ment1oned members,

saidfloatmg member foi-.returning liquid ,j

and means mounted on leakingpast bothA of said packings to said chamber. A L A cushion device comprising teleticopically arranged members forming a closed chamber-,having two effective diameters, a sliding joint for er ch diameter, and a pump the inletv pressure -side of one of said sliding joints and tlie outlet of which connects with the interir'y of said chamber.

4. A cushion device comprising telescopically arranged members forming a closed chamber of .two effective diameters, a slidg oint for each diameter, a pumpthe inlet' of which connects with the low pres'.- suref side orf. the sliding joint for the largest diameter' and the outletof which connects with'theinterior of said chamber.

5'. `A cushion device' comprlsing three teleing scopically arranged members having A-two sliding joints therebetween and -forming: a closed chamber of two effective diameters,

and a pump` within said chamber having its inlet connected to the low pressure side of one of said sliding 'joints and its outlet connecting with the interior of said chamber. y 6; A cushion device comprising three telescopically arranged cylinders forming `a closed chamber having two effective diameters and two sliding joints,

said sliding joints and a pump within the"- chamber the inlet of which connects with the low pressure side of one ot' said packings and the outlet of which connects with the interior of said chamber, within said chamber for operating pump.A y 7. A cushion devic( comprising two cupped members arranged so that their open ends face one another, and relatively said device when the load load. cylinder,

of which connects with the ow 9 j supported member,

' with means for reducing prising a v porting A 'and for decreasing packing for and means' BEST AVAiLAsLE COP.,

sliding cylinders connecting said members and with themA forming 'a closed chamberr having two- 'effective diameters' and two sliding joints, liquid and gaseous vfluids within said chamber, and means for return- .ing the liquid passing said joints to the interior of the chamber. y

8. A cushion device comprising an inner or light load cylinder', an outer or heavy and an intermediate cylinder telescopically arranged between said inner and .outer cylinders, and with them forming a closed chamber having two effective diameters and two sliding joints, packing for said joints and a pump within said chamber the inletof which connects with theI low pressure side of one of said-'joints and the4 outlet of which connects with the interior of said chamber.

9. A cushioning device comprising telescopically arranged members having sliding joints therebetween and forming an inclosed chamber of variable volumetric capacity, and means for increasing the effec tive load supporting area of-'the device when the load supported thereby is v increased and for decreasing the eective'load supporting area of thehdevice duringlight loads on the device, and a pump mechanism mounted onsaid means for returning leakage liquid to said chamber.

10. A cushioning device comprising a a load supporting memA ber, andan intermediate sleeve coperating therewith to form a closed chamber of variable volumetriccapacity, in combination the effective area of the load supporting member during light loads and for increasing its effective area during heavy loads. ,f

r3.1L A pneumatic cushioning devicev comsupported member' and aloa'd supmember inclosin'g a chamber of variable :yolumet'ric' capacity, in combination with means. foi' increasing the unbalanced effective load supporting area ofthe `load supporting member during heavy loads its el'ective area during light loads, anda pump mechanism carried by said meansfor returning leakage liquid back to said chamber.-

12. A cushioning .device comprising a supported member, ber, and a floating sleevegextending between said members and coperating therewith to form a'closed chamber of variable volumet ric capacity, said sleeve being provided with a load supporting memmeans for forcing it into locaing engagetherewith to form apressure chamber -of variable volumetric capacity, said intermediate sleeve being provided with an extendi ing Hange subjected onfone side to the pressure within the chamber and on the other side tov exterior pressure, `and means for locking the sleeve i-nto engagement with th'e supported member or with the supporting member, dependent on the relative positions of .the members. i 14, A cushioning device, comprising tw `relatively movable telescopicallyl arranged members inclosing a chamber of variable volumetric capacity, a cylindrical memoer located within telescopic members, a

packing between the inner face of said cy*` lindrical member and one of said telescopically arranged members, a packing between 4the outer face of said 4cylindrical member and the other of said telescopically arranged members,'and means mounted on the eylin drieal member adapted toA return liquid leaking'from said chamber past both said packings back to the chamber:

15. A pneumatic cushioning device, com

prising a supported member,- and a load supporting member.- inclosing a chamber of vvariableY volumetric capacity, in combination With a cylindrical rmember located within said first mentioned members and so arranged that one end`is subjected to the pressure Within said chamber and the other end is subjected to exterior pressure, and, means carried by the cylindrical member for returning liquid leaking from the chamlbei' back to the chamber'.

In testimony whereof, I haveA hereunto subscribed my name this 8th day of May, 

